Core body for transfer apparatus

ABSTRACT

A core body includes a structure having a plurality of connected unit cells. At least one unit cell has one or more sidewalls that are curved and define a portion of an inner passageway within and through the unit cell. The one or more sidewalls define multiple orifices and include a cone disposed between at least some of the orifices. A dimple is defined along an outer surface of the unit cell at the cone. The outer surface at least partially defines an outer passageway that is sealed from the inner passageway by the one or more sidewalls. The one or more sidewalls are configured to transport one or more of thermal energy from a first fluid or a component of the first fluid flowing in the inner passageway to a second fluid flowing in the outer passageway without the first fluid mixing with the second fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims priority toU.S. Non-provisional Application No. 17/524,536, entitled “Core Body forTransfer Apparatus,” filed Nov. 11, 2021, which claims priority benefitsfrom U.S. Provisional Application No. 63/176,961, filed Apr. 20, 2021,and both of these priority applications are hereby incorporated byreference in their entirety.

BACKGROUND Technical Field

The apparatuses and methods described herein relate to apparatuses thattransfer heat between different fluids or filter particles.

Discussion of Art

Cooling apparatuses transfer heat from one fluid to another fluid acrossor through a barrier. One example of a cooling apparatus is an exhaustgas recirculation (EGR) cooler, which transfers or draws heat away fromrecirculated engine exhaust gas to a coolant, such as water, as theexhaust gas and coolant flow through the cooler. The coolers have shellsin which cores are disposed. The cores have separate channels for thecoolant and the exhaust gas. The cores are designed to enable heattransfer from one fluid to another fluid and/or the filtering of acomponent from one fluid through a barrier without allowing the twofluids to mix. One problem with these coolers is the manufacture andassembly of complex core geometries within a shell of the cooler. Thefluid channels of the core may snake through the core in non-linearpaths to encourage fluid-wall interactions for heat transfer and/orfiltering without excessively increasing fluid flow resistance and/orpressure drop through the core. Such complex geometries that providetortuous flow channels while maintaining physical separation between thedifferent fluids through the core may be able to be constructedaccording to conventional processes, such as casting.

Additive manufacturing can be used to three-dimensionally print or formthe complex core geometry. However, due to limitations in additivemanufacturing technology, printing complex repeating geometriestypically requires forming support structures underneath some downskinsurfaces to maintain design integrity and structural integrity. Thesupport structures are undesirable for several reasons, as the supportstructures clog the flow channels, are difficult or impossible to removewithout detrimental effect to the core, and slow the additivemanufacturing process. One way to avoid the formation of supportstructures within the core geometry is to reduce the size of therepeating units or cells in the core body. But, reducing the unit cellsize would undesirably increase flow resistance through the core,increase the pressure drop through the core, and reduce manufacturingspeed and increase manufacturing costs (e.g., to print more unit cellsper given volume than if the unit cells are larger). This may result inreduced throughput and transfer effectiveness. It may be desirable tohave a system and method that differs from those that are currentlyavailable.

BRIEF DESCRIPTION

In one or more embodiments, a core body is provided that includes astructure having a plurality of connected unit cells, and at least oneunit cell of the plurality of connected unit cells has one or moresidewalls that are curved and have an inner surface that defines atleast a portion of an inner passageway within and through the unit cell.The one or more sidewalls of the unit cell define multiple orifices suchthat a first fluid can ingress the unit cell through one of the orificesand can egress the unit cell through another of the orifices. The one ormore sidewalls include a cone disposed between at least some of theorifices of the unit cell. The one or more sidewalls have an outersurface, and a dimple is defined along the outer surface at the cone.The one or more sidewalls have an edge that extends around the orificesof the unit cell. The edges of different unit cells connect to eachother, and the outer surface at least partially defines an outerpassageway that is sealed from the inner passageway by the one or moresidewalls of the unit cell. The outer passageway is configured to enableflow of a second fluid therethrough. The one or more sidewalls of theunit cell are configured to transport one or more of thermal energy fromthe first fluid or a component of the first fluid flowing in the innerpassageway to the second fluid flowing in the outer passageway withoutthe first fluid mixing with the second fluid.

In one or more embodiments, a core body is provided that includes astructure having a plurality of connected unit cells, and at least oneunit cell of the plurality of connected unit cells has one or moresidewalls that are curved and have an inner surface that defines atleast a portion of an inner passageway within and through the unit cell.The one or more sidewalls of the unit cell define at least four orificessuch that a first fluid can ingress the unit cell through one of theorifices and can egress the unit cell through another of the orifices. Aportion of the one or more sidewalls disposed between three of theorifices has a triangular shape, and the three orifices are spaced apart120 degrees along a circumference of the unit cell. The one or moresidewalls have an edge that extends around the orifices of the unitcell. The edges of different unit cells connect to each other to atleast partially define outer passageways that are sealed from the innerpassageway of the unit cell and inner passageways of other unit cells bythe one or more sidewalls of the unit cells. The outer passageways areconfigured to enable flow of a second fluid therethrough. The one ormore sidewalls of the unit cells are configured to transport one or moreof thermal energy from the first fluid or a component of the first fluidflowing in the inner passageways to the second fluid flowing in theouter passageways without the first fluid mixing with the second fluid.

In one or more embodiments, a method (e.g., for forming a core body) isprovided. The method includes additively manufacturing a core body bysequentially depositing layers of material at least partially on topeach other in a build direction to form a structure comprised of aplurality of connected unit cells. At least one unit cell of theplurality of connected unit cells has one or more sidewalls that arecurved and have an inner surface that defines at least a portion of aninner passageway within and through the unit cell. The one or moresidewalls of the unit cell define multiple orifices such that a firstfluid can ingress the unit cell through one of the orifices and canegress the unit cell through another of the orifices. The one or moresidewalls include a cone disposed between at least some of the orificesof the unit cell. The one or more sidewalls have an outer surface, and adimple is defined along the outer surface at the cone. The one or moresidewalls have an edge that extends around the orifices of the unitcell, and the edges of different unit cells connect to each other. Theouter surface at least partially defines an outer passageway that issealed from the inner passageway by the one or more sidewalls of theunit cell. The outer passageway is configured to enable flow of a secondfluid therethrough. The one or more sidewalls of the unit cell areconfigured to transport one or more of thermal energy from the firstfluid or a component of the first fluid flowing in the inner passagewayto the second fluid flowing in the outer passageway without the firstfluid mixing with the second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive subject matter may be understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 illustrates one example of a transfer apparatus;

FIG. 2 illustrates a first cross-sectional view of the apparatus shownin FIG. 1 ;

FIG. 3 illustrates a cross-sectional view of a portion of a core body ofthe transfer apparatus according to an embodiment;

FIG. 4 illustrates an additional cross-sectional view of the apparatusshown in FIG. 1 ;

FIG. 5 illustrates another cross-sectional view of the apparatus shownin FIG. 1 ;

FIG. 6 illustrates another cross-sectional view of the apparatus shownin FIG. 1 ;

FIG. 7 illustrates a first cross-sectional view of the transferapparatus along line 7-7 in FIG. 1 ;

FIG. 8 illustrates a second cross-sectional view of the transferapparatus taken along a plane that is orthogonal to the line 7-7 in FIG.1 ;

FIG. 9 illustrates another cross-sectional view of the transferapparatus along line 7-7 shown in FIG. 1 ;

FIG. 10 is a perspective view of the core body of the transfer apparatusaccording to an embodiment;

FIG. 11 is a cross-sectional view of the core body shown in FIG. 10 ;

FIG. 12 illustrates a first cross-sectional view of the core body alongline 12-12 shown in FIG. 11 ;

FIG. 13 illustrates a second cross-sectional view of the core body alongline 13-13 shown in FIG. 11 ;

FIG. 14 illustrates a third cross-sectional view of the core body alongline 14-14 shown in FIG. 11 ;

FIG. 15 illustrates a fourth cross-sectional view of the core body alongline 15-15 shown in FIG. 11 ;

FIG. 16 is the cross-sectional view of the core body shown in FIG. 11with enlarged areas showing upper and lower cones according to anembodiment; and

FIG. 17 illustrates a flowchart of one example of a method for creatinga transfer apparatus or a component thereof.

DETAILED DESCRIPTION

At least one embodiment of the inventive subject matter described hereinrelates to a monolithic (e.g., single body) transfer apparatus thataccommodates thermal expansion of a core through a unique flexiblediaphragm connection at an inlet and outlet of the apparatus. Thisflexible diaphragm can be more easily displaced than some known slidingjoints and/or seals without causing unacceptable stresses in an outershell (e.g., housing) or core. The transfer apparatus can cause acooling medium (e.g., coolant) to be forced through the core without adirect connection of the shell to the core. The cooling medium can beforced by forming (e.g., via additive manufacturing) different sizedvolumes in different locations between (a) the diaphragm and (b) theshell and core to increase the pressure of the coolant in locations thatforces the coolant through more of the core (relative to some knowncoolers using sliding seals between the core and shell). The flexiblediaphragm can be integrally formed with the core and shell via additivemanufacturing to provide a completely integrated wall that allows forminimal to no coolant leakage between the core and the shell. Printingthe shell and core as a single piece body permits tight control of theinterface between the two geometries (the core and the shell).

Alternatively, the core and shell described herein can be separatelyformed, and then the core placed into the shell. For example, the shellcan be cast, additively manufactured, injection molded, or the like, andthe core can be additively manufactured and placed into the shell. Theflexible diaphragm can be formed as part of the shell or core, or may bea separately formed and then placed between the shell and the core. Theshell and core can then be welded together to form a completelyintegrated solid. Aspects and features of the design and manufacturingmethodology may be determined using features disclosed herein.

The use of additive manufacturing of the flexible diaphragm and/or thecore can enable the core to be fit into a wide variety of applicationspaces. The shell similarly can be made to avoid interference withexisting components for retrofit applications.

The apparatuses described herein can maximize or increase useful livesof the apparatuses relative to some known EGR coolers by accommodatingthermal cycling without a sliding interface. Additionally, because thereis no moving or sliding interface to seal with a gasket, O-ring, or thelike, the apparatus can withstand extreme temperatures in conditions.One such condition is a dry run condition for an engine, in which engineexhaust gas flows though the apparatus without a cooling medium alsoflowing through the apparatus. This condition can expose the apparatusto temperatures of over 1,000° F. (or 540° C.). Extreme temperaturesmay, in turn, cause extreme thermal expansion. The flexible diaphragmsof inventive embodiments described herein may flex and accommodate thethermal expansions.

Other embodiments of the inventions described herein relate to the core,or core body, of a transfer apparatus. The core body may be determinedor designed to have repeating, interconnected unit cells that defineinner passageways for one fluid through the unit cells and outerpassageways for another fluid outside of the unit cells without the twofluids physically mixing with each other. For example, the innerpassageways are not fluidly connected to the outer passageways. The unitcells have sidewalls between the inner passageways and the outerpassageways that permit the transfer of thermal energy (e.g., heat)across the sidewalls from the hotter fluid to the cooler fluid. Thesidewalls optionally may be determined or designed to permit thetransfer (e.g., filtering) of one or more components from a first fluidthrough the sidewalls into the second fluid. The first fluid and/or thesecond fluid optionally may include more than one fluid type,composition, or compound. For example, the first fluid may be a coolantthat is introduced into the inner passageways of the core, and thesecond fluid may be multiple different fluids that are introduced intothe outer passageways. The multiple different fluids can mix with oneanother within the core and transfer heat to the coolant through thethin sidewalls.

The core body according to an embodiment has a complex, repeatinggeometry that separates fluids and is printable without forming supportstructures. The geometry of the core body enables the option forrelatively large, unsupported unit cell dimensions. The larger unitcells can provide reduced flow resistance and pressure drop through thecore body (e.g., increased fluid throughput) relative to smaller unitcells. The unit cells are hollow, so increasing the size of the unitcells may actually reduce the amount of material deposited during theadditive manufacturing process relative to smaller unit cells, therebyincreasing the print speed and reduce printing and/or material costs.

The ability to additively manufacture the core body without supportstructures also enables the core body to be formed in customized shapesbased on a specific application. In the EGR cooler, the core body can beprinted to conform with the specific inner volume or form factor of theshell. Optionally, the core body may be integrally formed with the shellduring a common additive manufacturing process to provide a monolithic(one-piece) EGR cooler. Integrally forming the core body with the shelleliminates seams between the components which can beneficially eliminatepotential leak paths during use and operation of the EGR cooler.

FIG. 1 illustrates one example of a transfer apparatus 100. Theapparatus can be used to transfer energy or components between twomedia. For example, the apparatus can transfer thermal energy (e.g.,heat) from one fluid to another fluid (to cool one fluid) or cantransfer a component from one fluid to another fluid (to filter thecomponent from one fluid). The apparatus includes an outer shell 102 inwhich an internal heat transfer core body and a flexible diaphragm (bothshown in FIG. 2 ) are disposed. The shell has a first inlet 110 thatreceives a first fluid 112, a second inlet 114 that receives a secondfluid 116. The first and second fluids may be gases and/or liquids. Forexample, the first fluid may be a coolant or cooling medium, such as aheat transfer fluids (e.g., water, refrigerant, other synthetic ornatural fluids). The second fluid can be a gas exhaust from an engine,or may be another liquid. The second fluid can be warmer than the firstfluid prior to entry into the apparatus.

The shell also includes a first outlet 120 through which the first fluidis directed out of the shell and a second outlet 118 through which thesecond fluid is directed out of the shell. As described herein, the corebody has inner passageways (shown in FIG. 2 ) through which the firstfluid flows through the core from the first inlet to the first outletand outer passageways (shown in FIG. 2 ) through which the second fluidflows through the core from the second inlet to the second outlet. Asthe first and second fluids flow through the corresponding inner andouter passageways, heat can be transferred from the second fluid to thefirst fluid (across or through the material forming the core).Alternatively, the material forming at least part of the core can filterone or more components from the second fluid to the first fluid (or fromthe first fluid to the second fluid). The first fluid optionally mayinclude multiple different fluids that mix together within the innerpassageways of the core. The second fluid optionally may includemultiple different fluids that mix together within the outer passagewaysof the core.

The inner passageways can keep the first fluid separate from the secondfluid, and the outer passageways can keep the second fluid separate fromthe first fluid. The inner passageways can direct flow of the firstfluid from the first inlet to the first outlet. The first outlet candirect the first fluid (which has now been heated by the second fluid orhas received one or more components from the second fluid) to a deviceor system that cools (or filters) the first fluid and returns the firstfluid to the first inlet. The outer passageways can direct flow of thesecond fluid from the second inlet to the second outlet. The secondoutlet can direct the second fluid (which has now been cooled by thefirst fluid or has had the one or more components removed and passed tothe first fluid) back to the engine (in an EGR cooler) or to anotherlocation.

FIG. 2 illustrates a first cross-sectional view of the apparatus shownin FIG. 1 . The cross-section shown in FIG. 2 is along a plane that isparallel to the plane of FIG. 1 and extends through an axial center ofthe core body. The internal heat transfer core body 204 inside the shellincludes a single structure or web of material 201 in a shape that formsthe first interior passageways 522 and the second interior passageways524. The first interior passageways 522 and the second interiorpassageways 524 of the core body are also referred to herein as innerpassageways and outer passageways, respectively. Alternatively, the coremay be formed from multiple bodies or webs of material that are in ashape that forms the inner and outer passageways.

The apparatus includes a flexible diaphragm 206 that couples and extendsfrom the core body to an interior surface 208 of the outer shell. Thediaphragm is flexible. The diaphragm may be more flexible than the shelland/or the core body. For example, when receiving force, the diaphragmmay bend, get displaced, or otherwise modify its shape to a greaterextent than the shell and/or the core body receiving the same force. Thediaphragm forms a flexible transition between (a) each of the firstinlet and the second inlet of the shell and (b) the core body. Theflexible diaphragm forms a seal that prevents the first fluid flowingthrough the inner passageways of the core body from flowing into theouter passageways of the core body. The flexible diaphragm canaccommodate variations in the distance between the core body and theinterior surface of the outer shell, such as variations attributable tothermal expansion and contraction. For example, the shell and the corebody may expand by different amounts or distances due to the differentsizes of the shell and core body (even when the shell and core body areformed as a monolithic body and formed from the same material). Theflexible diaphragm can flex due to the different expansions of the shelland core body without tearing or otherwise breaking the seal between theshell and core body. This seal maintains fluid separation of the innerand outer passageways of the core body.

FIG. 3 illustrates a cross-sectional view of a portion of the core bodyaccording to an embodiment. The cross-section shown in FIG. 3 is along aplane that is parallel to and offset from the plane of FIG. 2 . Theinner passageways 522 are on one side of the body or web of material ofthe core, and the outer passageways 524 are on the opposite side of thebody or web of material of the core. For example, the body or web ofmaterial includes thin sidewalls 210 that partition the innerpassageways from the outer passageways.

The sidewalls are part of unit cells 212 of the core body, which aregeometric shapes that repeat throughout the core body. The unit cellsare interconnected. For example, the core body is a structure that has aplurality of connected unit cells. In one or more embodiments, the unitcells have generally spherical shapes defined by the sidewalls, asindicated by the circular cross-sections shown in FIG. 3 . The shapes ofperipheral unit cells located along the cylindrical side of the corebody may be distorted to deviate from the spherical shape as necessaryto provide a desired overall size and/or shape of the core body. Theunit cells may have other shapes in other embodiments. Suitable othershapes can include cubic, parallelepiped, prism, or the like. The innerpassageways are defined within and extend through the unit cells. Theouter passageways are outside of the unit cells and represent theunoccupied spaces between the unit cells.

As shown in FIG. 3 , the inner passageways are separated from the outerpassageways by the sidewalls. The inner passageways within two of theunit cells are filled in by diagonal lines in FIG. 3 to clearly show thedistinction between the inner passageways and the outer passageways thatsurround the inner passageways in the illustrated cross-sectional view.The sidewalls may be relatively thin. Suitable sidewall thicknesses maybe less than 3 millimeters (mm). The sidewalls of the unit cells connectto one another at tubular extensions 842 (shown in FIG. 10 ) to fluidlyconnect the inner passageways throughout the core body and keep thefirst and second fluids physically separated from one another. Heat maybe transferred between the first fluid and the second fluid through thesidewalls without mixing any other part of the first fluid and thesecond fluid together in the inner or outer passageways in oneembodiment. Alternatively, the sidewalls may include pores that filterone or more components from the second fluid to the first fluid (or fromthe first fluid to the second fluid) without mixing any other part ofthe first fluid and the second fluid together in the inner or outerpassageways. In the illustrated embodiment, the fluid within the innerpassageways is a gas, and the fluid within the outer passageways is acoolant. Optionally, the gas in the inner passageways may be hot gasexhausted from an engine, and the coolant within the outer passagewaysmay be water. The water can absorb heat from the gas through thesidewalls of the unit cells as the water flows through tortuous pathsbetween the unit cells along the outer passageways. The water enters thecore body through inlet openings 214 of the outer passageways along theperipheral surface of the core body.

FIGS. 4, 5, and 6 include additional cross-sectional views of theapparatus shown in FIG. 1 . The cross-sectional views of FIGS. 4, 5, and6 are taken along the same plane as the cross-sectional view of FIG. 2 .The flexible diaphragm has a curved conical shape that extends inwardfrom the interior surface of the shell to the core body. This conicalshape provides a conical transition between the shell and the core body.The conical transition can be controlled to vary in length (e.g., thedistance from the interior surface of the shell to the core body) and/orangle of intersection to the shell and core so that the flexiblediaphragm can be included in a variety of shapes of the core body and/orshell. The ability to customize the size and/or shape of the flexiblediaphragm allow for the transfer apparatus to be effectively determinedor designed and packaged for space constrained applications. While theshell is shown as having a cylindrical shape, the core body and/or shellcan have another shape, with the flexible diaphragm extending betweenand sealing the shell to the core body. For example, the shell may havea rectangular shape, with the flexible diaphragm extending between andsealing the shell to the core body.

The flexible diaphragm is flat in the illustrated embodiment. Forexample, the diaphragm may have a smooth, conical shape withoutundulations, waves, dimples, protrusions, or the like. Alternatively,the diaphragm may have an uneven surface with undulations, waves,dimples, protrusions, or the like.

As shown, the flexible diaphragm may be thinner than the outer shell. Aninner surface 432 of the flexible diaphragm faces the core body andfaces away from the portion of the inner surface of the shell that isbetween the second inlet and the second outlet of the shell. This innersurface of the flexible diaphragm may be oriented at an angle that isless than forty-five degrees to the interior surface of the outer shell.Alternatively, the inner surface may be oriented at an angle that isless than thirty degrees or less than fifteen degrees to the interiorsurface of the outer shell. An opposite, outer surface 430 of theflexible diaphragm faces away from the core body and can face theportion of the inner surface of the shell that is between the secondinlet and the second outlet. This outer surface of the flexiblediaphragm can be oriented at an angle that is more than forty-fivedegrees to the interior surface of the outer shell. Alternatively, theouter surface may be oriented at an angle that is greater thanfifty-five degrees or greater than seventy-five degrees to the interiorsurface of the outer shell.

FIG. 7 illustrates a first cross-sectional view of the transferapparatus along line 7-7 in FIG. 1 . FIG. 8 illustrates a secondcross-sectional view of the transfer apparatus. The cross-sectional viewin FIG. 8 is taken along a plane that is orthogonal to the line 7-7 inFIG. 1 . As shown in FIG. 1 , the shell includes elongated indentations122 on opposite sides of the shell. The indentations can be elongated indirections that extend from the second inlet to the second outlet. Theindentations can be disposed midway between the first inlet and thefirst outlet along a circumference of the shell, as shown in FIG. 8 .For example, the indentations may be on opposite sides of the shell.Alternatively, the indentations may be in another location and/or morethan two indentations may be included in the shell. The indentations canreduce the distance or spatial gap between the inner surface of theshell and the core body. For example, the core body can be disposed afarther distance 434 from the inner surface of the shell in locationsaway from the indentations (as shown in FIGS. 5 and 8 ) and a closerdistance 600 at the indentations (as shown in FIGS. 7 and 8 ).

The decreased distance between the shell and the core in theindentations can help force the first fluid from the first inlet towardand out of the first outlet. These indentations reduce the volume inwhich the first fluid flows between the first inlet to squeeze the firstfluid and help force the first fluid toward the first outlet.

FIG. 9 illustrates another cross-sectional view of the transferapparatus along line 7-7 shown in FIG. 1 . In this illustratedembodiment, the flexible diaphragm interfaces with the interior surfaceof the shell with rounded interfaces. For example, instead of havingcorners or interfaces between straight lines at the interface betweenthe inner surface of the flexible diaphragm and the inner surface of theshell and at the interface between the outer surface of the flexiblediaphragm and the inner surface of the shell, the flexible diaphragmand/or shell can be formed with fillets at one or both of theseinterfaces. The flexible diaphragm and/or shell can have an inner fillet726 and an outer fillet 728 on opposite sides of an interface betweenthe flexible diaphragm and the shell. These fillets can be roundedinterfaces that increase the flexibility of the diaphragm (when comparedwith interfaces that do not include rounded edges or fillets). The innerfillet may have a smaller radius of curvature than the outer fillet, asshown in FIG. 9 .

FIG. 10 is a perspective view of the core body of the transfer apparatusaccording to an embodiment. The unit cells of the core body have cellbodies 840 and tubular extensions 842. The cell bodies and the tubularextensions are defined by the curved sidewalls of the unit cells. Eachcell body defines a main cavity 844 of the unit cell. The cell body mayhave a generally spherical shape. For example, the curved sidewall ofthe cell body may be spherical along portions of the cell body spacedapart from the tubular extensions, cones, and other non-uniformities.The tubular extensions extend between the cell bodies and physicallyconnect the unit cells. For example, a first unit cell is physicallyconnected to a second unit cell via a first tubular extension thatextends from the cell body of the first unit cell to the cell body ofthe second unit cell. The first unit cell may be physically connected toa third unit cell via a second tubular extension that extends from thecell body of the first unit cell to the cell body of the third unitycell. In an embodiment, the core body is a single, monolithic structure,such that the cell bodies and the tubular extensions are integrallyformed and define seamless interfaces. The tubular extensions are hollowand define flow channels 846 to fluidly connect the main cavity of onecell body to the main cavity of another cell body. The main cavity ofthe first unit cell may be fluidly connected to the main cavity of thesecond unit cell via the flow channel of the first tubular extension.The main cavity of the first unit cell may be fluidly connected to themain cavity of the third unit cell via the flow channel of the secondtubular extension.

An inner surface 800 of the curved sidewalls defines at least a portionof the inner passageways that extend within and through the unit cells.For example, the inner surfaces 800 of the curved sidewalls may definethe main cavities and the flow channels of the tubular extensions. Outersurfaces 802 of the curved sidewalls define the outer passageways in theintervening spaces between the unit cells. The unit cells permit flow ofa first fluid through the structure within the main cavities of the cellbodies and the flow channels of the tubular extensions (e.g., within theinner passageways) without the first fluid mixing with a second fluidthat is disposed in the spaces between the unit cells (e.g., within theouter passageways).

The core body has a height extending from a bottom end 810 to a top end812 (opposite the bottom end). The core body has a generally cylindricalshape in the illustrated embodiment to conform to the interior of theshell. For example, the core body has an outer side 814 that iscircumferential and extends from the top end to the bottom end. Thesurface along the outer side has grooves and undulations attributable tothe curved sidewalls of the unit cells. The inner passageways throughthe unit cells permit the first fluid to generally flow along thevertical height of the core body, such as from the top end down and outthrough the bottom end. The outer passageways can permit the secondfluid to flow laterally, radially, and circumferentially (as well asvertically). For example, the second fluid can enter the outerpassageways through the cylindrical outer side of the core body as shownin FIGS. 3 and 8 .

The unit cells in the core body are arranged in an array. In anembodiment, the cells are disposed in multiple rows 816 that are stackedalong the height of the core body. The illustrated embodiment shows areleast portions of four rows 816 a, 816 b, 816 c, 816 d of unit cells.Each row includes multiple unit cells that are spaced apart from eachother. The unit cells in one row may be staggered or offset from theunit cells in the row above or below. For example, a single unit cell ina first row may be disposed at least partially above multiple unit cellsin an adjacent row, such that a footprint of the unit cell wouldpartially overlap and intersect with multiple unit cells in the adjacentrow. Staggering the positions of the unit cells encouragesfluid-sidewall contact interactions by forcing the first fluid to snakethrough the inner passageways rather than essentially freefall throughthe core body. The heat transfer and/or material transfer occurs via thefluid-sidewall interactions. In an embodiment, a given unit cell in anintermediate row (e.g., 816 b, 816 c) is interconnected to unit cells inthe rows above and below via the tubular extensions. The unit celloptionally may not be directly fluidly connected to other unit cells inthe same row. For example, the unit cell is not connected via any of thetubular extensions to another unit cell in the same row.

The unit cells of the core body may be the same size and shape as oneanother, except for the peripheral cells along the outer side that aredistorted to maintain the designated size and shape of the core body.The sidewalls of the peripheral unit cells along the outer side of thecore body may be flatter (e.g., have less curvature) relative to thesidewall curvature along the interior unit cells. The sidewalls at theouter side close the inner passageways to maintain the mechanicalseparation between the first and second fluids.

The core body shown in FIG. 10 has fewer unit cells in the array thanthe core body shown in FIG. 8 for example, to demonstrate that thenumber and size of the unit cells may be selected based onapplication-specific parameters. Suitable parameters that may be takeninto account can include amount of thermal energy transfer, fluid flowresistance, fluid pressure drop, and the like. The core body accordingto at least one embodiment is formed to have relatively large unit cellsizes to reduce flow resistance and pressure drop and increasemanufacturing efficiency (e.g., less material and printing) whileproviding sufficient fluid-sidewall interactions to enable desiredtransfer performance.

The curved sidewalls of the unit cells define multiple orifices 804along the cell bodies. The orifices represent portions of the innerpassageways through the unit cells. For example, the first fluid canenter a respective main cavity of a cell body through one of theorifices of the cell body and can egress the main cavity through anotherof the orifices. The orifices fluidly connect the main cavities ofdifferent cell bodies to the flow channels of the tubular extensions.

In an embodiment, the orifices of a unit cell are connected to otherunit cells, via the flow channels of the tubular extensions, to fluidlyconnect the main cavities of the unit cells through the core body. Eachorifice of a unit cell may be fluidly connected to a different unitcell. For example, the curved sidewall of a first unit cell may define afirst set of one or more orifices and a second set of one or moreorifices. The first set of orifices fluidly connects to a first subsetof the unit cells via a first group of the tubular extensions. Thesecond set of orifices fluidly connects to a second subset of the unitcells via a second group of the tubular extensions. The first set oforifices optionally may include a first orifice fluidly connected to asecond unit cell, a second orifice fluidly connected to a third unitcell, and a third orifice fluidly connected to a fourth unit cell. Eachtubular extension extends from one orifice of one unit cell to oneorifice of another unit cell. The tubular extensions seal the innerpassageways from the outer passageways.

In an embodiment, connected unit cells are integrally connected to eachother to define seamless interfaces between the unit cells. For example,the core body may be a single, monolithic structure with the unit cellsinterconnected at seamless interfaces. The cell bodies may be integrallyconnected to the tubular extensions at the seamless interfaces. Thematerial composition of the core body may be selected based onapplication-specific factors. For example, materials with good thermalconductivity, such as one or more metal materials, may be used for heatexchange applications of the transfer apparatus. Other types ofmaterials, such as polymer materials, ceramic materials, or compositematerials, may be utilized to form the core body for filteringapplications in which at least a component of the first fluid or thesecond fluid transfers into and/or through the sidewalls of the unitcells.

According to at least one embodiment, the core body is produced viaadditive manufacturing. The core body is formed by sequentiallydepositing layers of build material at least partially on top of eachother in a build direction to eventually form the structure shown inFIG. 10 . The build material may be a powder that is deposited in a bedand then selectively heated to provide a designated location, size, andshape of each layer according to a design file. Alternatively, the buildmaterial may be a filament that is heated and selectively deposited by amovable effector head to provide the designated location, size, andshape of each layer according to the design file. In the illustratedembodiment, the core body may be additively manufactured in an upwardbuild direction 808. For example, the bottom end 810 may be formedinitially, and subsequent layers are stacked on top of each other untilthe top end 812 is eventually formed to complete the build process.Manufacturing steps may be iteratively improved using features disclosedherein.

FIG. 11 is a cross-sectional view of the core body shown in FIG. 10 .The cross-sectional view in FIG. 11 is taken along a plane that isorthogonal to the plane of the top end of the core body in FIG. 10 , andthe cross-section plane may bisect the core body. FIG. 11 shows thebisected view of two full unit cells, indicated by dashed circles, andmultiple partial unit cells. FIG. 11 shows four orifices 804 defined bythe sidewalls of each of the full unit cells. For example, two orificesare cross-sectioned at top-right and bottom-left areas of the cell, andtwo orifices are shown at top-left and bottom-right areas that extend adepth into the core body. A first unit cell has a first set 850 of oneor more orifices that connect to one or more unit cells in a firstadjacent row, and a second set 852 of one or more orifices that connectto one or more different unit cells in a second adjacent row. In anembodiment, at least some of the unit cells (e.g., the unit cells thatare not peripheral unit cells) have six total orifices. The other twoare omitted from FIG. 11 due to the cross-section. The first set mayinclude a first, second, and third orifice, and the second set mayinclude a fourth, fifth, and sixth orifice. The six orifices are open tothe flow channels of corresponding tubular extensions to connect thefirst unit cell with six other unit cells. The unit cells may have adifferent number of orifices in an alternative embodiment.

As shown in FIGS. 10 and 11 , the full unit cells (e.g., the unit cellsthat are not peripheral unit cells) may have a spherically-shape cellbody to define a generally spherical main cavity. For example, portionsof the sidewall of each unit cell between the orifices have convexcurvature relative to a center of the unit cell to define a sphere.Optionally, the unit cells may be at least slightly elongated to definean ellipse or oval. The portion of the curved sidewall between the firstset of orifices and the second set of orifices may have a circularcross-sectional shape. A diameter of the spherical main cavity may begreater than dimensions of the orifices and dimensions of the flowchannels of the tubular extensions. The diameter of the spherical maincavity may be greater than cross-sectional dimensions of the outerpassageway (e.g., the spaces between the unit cells).

The unit cells in adjacent rows may be staggered. The inner passagewaysmay extend at oblique angles relative to the row planes and the verticalheight of the core body, which encourages fluid and sidewallinteraction. A line 821 extending from a center point 822 of a firstunit cell to the center point 822 of a second unit cell that isconnected to the first unit cell defines an angle 824 that is no lessthan 30 degrees and no greater than 60 degrees relative to the rowplanes (e.g., a horizontal plane). The angle according to a morepreferred range may be between 35 degrees and 45 degrees. The angle morespecifically may be between 40 degrees and 42 degrees. These angles maybe selected to ensure sufficient printability and print quality of theadditively manufactured core body, and also to provide efficient cellrow packaging.

The dimensions of the inner passageways and the outer passageways varyalong the lengths thereof. Along the inner passageways, the orificesdefine the narrow-most or limiting flow dimensions 818. The orifices ofthe unit cells may be larger than the narrow-most or limiting flowdimensions 820 in the outer passageways. The dimension 848 of the maincavity along the portion of the cell body between the first and secondsets of orifices may be greater than the dimensions 818, 820. As such,there may be less flow resistance within the cell bodies than throughthe tubular extensions and outside of the unit cells. In an embodiment,the inner passageways may occupy more the space within the core bodythan the outer passageways. For example, a collective volume of the maincavities and the flow channels of the tubular extensions within thestructure may exceed the collective volume of the unoccupied spacesbetween the unit cells.

The sizing of the flow dimensions and the passageways may be variedbased on the type of fluids that flow through the passageways and/or thedesired transfer that occurs between the fluids through the sidewalls.In an embodiment, the first fluid through the inner passageways is a hotgas, and the second fluid through the outer passageways is a coolantdesigned to absorb heat from the gas. In an alternative embodiment, thesizes of the unit cells and/or the spacing between the unit cells may bealtered such that the limiting flow dimensions in the outer passagewaysare larger than the limiting flow dimensions in the inner passagewaysand/or the outer passageways occupy more space in the core body than theinner passageways.

The unit cells include a conical feature, or cone, 826 disposed betweenat least some of the orifices of the respective unit cell. The cone 826projects towards the center point of the unit cell. The cone may belocated along the inner surface of the curved sidewall. The cone has anapex 830 that is located between the center point of the cell and theportion of the sidewall at the base of the cone. The cone 826 may behollow, and the portion of the cone along the outer surface of thesidewall may define a dimple 828. A few dimples of the cones are shownin the perspective view of FIG. 10 .

The cone is located at a base of the curved unit cell. For example, thecone may be disposed at the lower-most portion of the unit cell relativeto the direction of gravity. In an embodiment, the cone is located alonga centerline of the unit cell. When the unit cell is spherical orotherwise curved, the cone at the base or bottom of the unit cellenhances printability of the core body without requiring supportstructures. For example, as shown in FIG. 11 , the bases of the cellsare unsupported. Forming an inflection along the sidewall at the baseavoids issues associated with printing relatively flat surfaces and/orthe nadir of a curve without any supports. The cones enable the unitcells to retain the generally spherical shapes without printingstructures to support islands of build material during the manufacturingprocess. The cones also may prohibit fluid from accumulating within thesidewalls of the unit cells. For example, the first fluid, if a liquid,would run off the cone towards the orifices that surround the cone.

In an embodiment, the sidewalls of the unit cells also include a secondconical feature, or cone, 832 along a top portion of the unit cells. Thesecond cone is spaced apart from the first cone and disposed between adifferent set of the orifices of the unit cell relative to the firstcone. The first cone is referred to herein as a lower cone 830, and thesecond cone is referred to herein as an upper cone 832. The upper coneis hollow and defines a dimple 834. The upper cone projects in the samedirection as the lower cone relative the core body. For example, bothcones project toward the top end of the core body. The dimple of theupper cone is defined along the inner surface of the sidewall. The uppercone optionally may be colinear with the lower cone. The upper cone maybe included to improve the printability of the unit cells in the corebody, similar to the inclusion of the lower cone. The presence of theupper cone may eliminate a relatively flat area at the top of the curvedunit cells, which may be difficult to reliably print without underlyingsupports.

FIG. 12 illustrates a first cross-sectional view of the core body alongline 12-12 shown in FIG. 11 . FIG. 13 illustrates a secondcross-sectional view of the core body along line 13-13 shown in FIG. 11. FIG. 14 illustrates a third cross-sectional view of the core bodyalong line 14-14 shown in FIG. 11 . FIG. 15 illustrates a fourthcross-sectional view of the core body along line 15-15 shown in FIG. 11. The illustrations in FIGS. 12 through 15 represent top down views ofthe core body shown in FIG. 10 , sectioned along different parallelplanes. When the core body is additively manufactured from the bottom tothe top, the sections shown in FIGS. 12 through 15 can indicatedifferent chronological stages of the build process. The core body isformed using relatively thin sidewalls for printing efficiency bylimiting the amount of material to print, and for providing relativelylarge passageways inside and outside of the cells to limit fluid flowresistance and pressure drop.

The section of the core body shown in FIG. 12 includes a circle 900 atthe radial center and six half circles 902 surrounding the centralcircle. These shapes represent parts of seven unit cells in a first rowof the core body. Three small circular openings 904 are triangularlyarranged around the central circle. The small openings representportions of the dimples of lower cones of unit cells in row above. Thecircular segments 906 of the sidewalls that define the small openingsare portions of the lower cones shown in FIG. 11 .

The section of the core body shown in FIG. 13 includes three full unitcells and three partial, peripheral unit cells disposed in a second rowabove the cells in the first row shown in FIG. 12 . The unit cells inthe second row are sectioned by the cut line 13-13. The three full unitcells are spaced apart in a triangular arrangement. The outerpassageways are defined in the spaces between the unit cells in thesecond row. In an embodiment, each of the full unit cells is built ontop of and is individually connected, via corresponding tubularextensions, to multiple unit cells in the underlying row. Each full unitcell may be disposed above portions of three underlying unit cells.

Within the circular outline of each unit cell is a portion 910 of thesidewall disposed between multiple orifices. That portion defines thebase or bottom of the unit cell, and includes the lower cone. In FIG. 13, the portion of the sidewall that is visible has a generally triangularshape and is between three orifices. The three orifices are spaced apart120 degrees along a circumference of the unit cell. The lower cone maybe centrally located and equidistant between the three orifices disposedaround the triangular portion. Each of the three orifices visible withineach of the full unit cells is fluidly connected to a different unitcell in the row below. For example, the orifices connect each unit cellto the three underlying unit cells that the respective unit cell atleast partially extends above and overlaps. When the first fluid flowsthrough the inner passageway of a respective unit cell, the first fluidgets trifurcated into three connected cells. FIG. 13 also shows the topof the upper cone of the centrally-located unit cell 212 x.

The section of the core body shown in FIG. 14 includes three full unitcells and three partial, peripheral unit cells in a third row disposedon top of the cells in the second row. The arrangement of the unit cellsin the third row is inverse (e.g., flipped relative to) the arrangementof the unit cells in the second row. For example, the three full unitcells in FIG. 14 are triangularly arranged, similar to FIG. 13 , but thetriangle is flipped 180 degrees relative to the triangular arrangementin FIG. 13 . In an embodiment, the sidewalls of the full unit cells havethree orifices that fluidly connect the respective unit cell to threedifferent unit cells in the row above. For example, the cell 212 a inthe second row is fluidly connected to three cells 212 b, 212 c, 212 din the third row. The full unit cells according to the illustratedembodiment include six total orifices, including a first set of threeorifices that connect to cells in a row below, and a second set of threeorifices that connect to cells in a row above. The first fluid caningress a unit cell through one or more of the orifices and can egressthe unit cell through one or more of the other orifices.

FIG. 15 is a plan view of the core body showing the top end. The top ofthe core body includes multiple, incomplete unit cells within a fourthrow of the core body above the unit cells in the third row that areshown in cross-section in FIG. 14 . The unit cells shown in FIG. 15 havea similar arrangement and shapes as the unit cells in the first rowshown in FIG. 12 . In an embodiment, each row of unit cells in the corebody has one of three cell arrangements, and the rows alternate throughthe three cell arrangements in a repeating pattern along the height ofthe core body. The unit cells may be arranged in a different number ofrepeating configurations in an alternative embodiment.

FIG. 16 is the cross-sectional view of the core body shown in FIG. 11with enlarged areas showing the upper and lower cones 832, 826 accordingto an embodiment. In the illustrated embodiment, the lower cone islarger than the upper cone. For example, the base of the lower cone isbroader than the base of the upper cone. The lower cone also has agreater height from base to apex than the upper cone. The dimple 828 ofthe lower cone has a greater volume than the dimple 834 of the uppercone. The lower cone may be larger than the upper cone due toprintability considerations. In an alternative embodiment, the upper andlower cones may have the same sizes or the upper cones may be largerthan the lower cones.

The core body may be manufactured to have thin walls throughout. Forexample, wall thicknesses of the sidewalls may be less than 3 mm, evenat the thickest sections. In an embodiment, the sidewall thicknesses arebetween 0.3 mm and 1.5 mm (inclusive of the endpoints). The diameter ofthe orifices may be significantly larger than the wall thickness. Forexample, the orifice diameter may be at least 3 mm. In an embodiment,the orifices may be at least ten times the wall thickness. The orificediameter in such embodiment may be up to 15 mm or more. The sidewallsoptionally may vary in thickness within this relatively narrow range.For example, the sidewalls along the lower cone may be thicker than thesegments of the sidewalls that extend from the lower cone. Optionally,the sidewalls along the upper cone may also be thicker than the segmentsof the sidewalls extending from the upper cone. The lower cone wallthickness may be thicker than the upper cone wall thickness to supportthe larger size, and greater inflection, of the lower cone relative tothe upper cone.

The thin walls enable the core body to have relatively large unit cellsand orifices. For example, the unit cell dimensions, for full cells thatare not distorted along the periphery of the core body, may be between10 mm and 30 mm. For the spherical unit cells, the unit cell dimensionrefers to the inner diameter of the sidewalls. In an embodiment, theunit cell dimension is about 20 mm. The cell dimensions can be selectedbased on application-specific factors, such as fluid throughput andtransfer properties, rather than printability considerations. Forexample, known core bodies with repeating geometries have significantlysmaller cell sizes to avoid the use of internal support structureswithin the core body, or alternatively have larger cell sizes butinclude internal support structures. Known core bodies do not includelarge cell sizes without internal support structures.

FIG. 17 illustrates a flowchart of one example of a method 1000 forcreating a transfer apparatus, or a component thereof. The method can beused to create one or more embodiments of the transfer apparatus shownand/or described herein. The method can be performed by an additivemanufacturing system (e.g., a three-dimensional printing system) thatautomatically prints the transfer apparatus using an input file.Suitable input file formats may include STL, OBJ, AMF, 3MF, or the like.At step 1002, a layer of material is deposited onto a working surface.For example, a first layer of material used to form the transferapparatus can be printed onto a working surface from one or morefilaments. The working surface may be a platform or build plate of theadditive manufacturing system.

At step 1004, at additional layer of material is deposited onto theunderlying layer of material. This additional layer can be at leastpartially printed onto the layer of material that was deposited prior tothis additional layer. At step 1006, a decision is made as to whethermanufacture of the transfer apparatus is complete. If additional layersare to be deposited to complete forming of the entire transferapparatus, then flow of the method can return toward step 1004 so thatone or more additional layers can be deposited as described above (untilcreation of the transfer apparatus is complete). The layers can besequentially deposited at least partially on top of each other to formthe shapes of the shell, the flexible diaphragm, and the core body. By“at least partially,” it is meant that the entire layer or less than theentire layer can be printed on top of an underlying layer. If creationof the transfer apparatus is complete, then flow of the method canproceed toward step 1008. At step 1008, the transfer apparatus isremoved from the working surface. The transfer apparatus can then beused to transfer energy and/or components between fluids, as describedabove.

Optionally, the method can be used to form a component of the transferapparatus (without forming at least one other component of the transferapparatus. For example, a core body may be additively manufactured bysequentially depositing layers of material at least partially on topeach other in a build direction. The additive manufacturing can beperformed by a three-dimensional printing system, according toinstructions in an input design file, to produce the core body accordingto the embodiments described herein. For example, the method can beperformed to print the core body shown in FIGS. 10 through 16 .

Suitable processes include, for example, laser powder bed fusion,electron beam powder bed fusion, directed energy deposition (DED), andbinder jetting. Laser powder bed fusion involves depositing a layer ofpowder on a build plate and fusing selective portions of the power usinga ytterbium fiber laser that scans a CAD pattern. Laser powder bedfusion may include selective laser melting or sintering. At leastportions of the core body and/or transfer apparatus could be printedusing DED, which prints at a very fast rate. For example, DED could beused to print the shell of the transfer apparatus, which could then befused directly with the flexible diaphragm that connects to the corebody. Binder jetting creates a part by intercalating metal powder andpolymer binding agent that bind the particles and layers togetherwithout the use of laser heating. The material of the core body may beselected based at least in part on the proposed method of additivemanufacturing. For example, the binderjet materials that include thebinder and the metal (or ceramic, or cermet) may make the green form(e.g., the shape prior to sintering). The green form might be in thefinal shape, or may be shaped so that the sintered form is the finalshape.

The core body of the transfer apparatus according to the embodimentsdescribed herein is a three-dimensional structure with a web ofinterconnected unit cells arranged in a regular, repeating pattern.Properties and characteristics of the core body may be selected based onapplication-specific parameters and desired functionality. For example,properties such as the shape of individual (and repeated) cells withinthe structure can be selected to increase structural strength, thermallyconductivity, flow volume or throughput through the core body, surfacearea for fluid-membrane interactions, and the like. Optionally, theangles or slopes of the sidewalls, the thickness of the sidewalls, thematerial composition of the sidewalls, the size of the sidewalls, andother characteristics of the sidewalls such as the density, relativedensity, porosity, or the like, can be selected to obtain a desiredstrength, conductivity, surface area, density, heat dissipation ability,etc. The relative density represents the density of the material dividedby the density of the core body. The porosity represents a measurementof the amount of void material (e.g., air) occupying the volume.

The properties or dimensions may be uniform throughout the core body.Alternatively, may vary along the height, radial thickness, or the likeof the core body, such that one or more properties in one area of thecore body may differ from another area of the core body. Unit cells mayvary in shape, size, thickness or spacing throughout the core structure,to improve the performance characteristics of the heat exchanger. Forexample, the unit cell sizes (e.g., diameters), orifice diameters,spacing between unit cells, ratios between the sizes of the innerpassageways and the outer passageways, and/or sidewall thicknesses canbe selectively varied to control fluid flow, heat transfer, materialtransfer (e.g., filtering) into and/or through the sidewalls, and/or thelike. Varying the flow resistance can help spread fluid to areas thatmay naturally receive less fluid flow than other areas. The unit cellscloser to the radial center of the core body may be smaller or closertogether than the unit cells closer to the periphery or outer side ofthe core body. The small sizes may increase flow resistance through themore centrally-located inner passageways and/or outer passageways, whichmay force more fluid towards the periphery.

The core body may be formed of at least one plastic, ceramic, and/ormetal material. The plastic material may include or represent an epoxyresin, a vinylester, a polyester thermosetting polymer (e.g.,polyethylene terephthalate (PET)), polypropylene, or the like. Theceramic material may include or represent silica, alumina, siliconnitride, or the like. The metal material may include or representaluminum alloys, titanium alloys, cobalt chrome alloys, stainless steel,nickel alloys, or the like. The core body may be a composite including amixture of multiple materials, such as a plastic with a ceramic, aceramic with a metal (known as a cermet composite material), and/or aplastic with a metal. Optionally, the core body may represent areinforced composite, such as a fiber-reinforced plastic. Thefiber-reinforced plastic may include embedded fibers within a matrixlayer of the plastic. The fibers may be carbon fibers, glass fibers,aramid fibers (e.g., Kevlar®), basalt fibers, naturally-occurringbiological fibers such as bamboo, and/or the like. The reinforcedcomposite may be reinforced with other shapes of material other thanfibers, such as a powder or strips in other embodiments. Thereinforcements may be embedded within any of the plastics listed above.The cermet composite material may be composed of any of the ceramics andthe metals listed above. For the additive printing process, thematerials may be provided in particle form, such as in a powder, and theprinting system selectively fuses the particles together to form eachlayer of the solid build part.

The additive manufacturing system and/or post-printing instruments maybe controlled to determine and to provide the core body with a specificsurface finish that affects how the core body interacts with the fluidsflowing through the core body. For example, a rougher surface finish mayincrease flow resistance, increase thermal transfer, and/or increasematerial transfer through the sidewalls relative to smoother surfacefinishes. Optionally, the surface finish may be varied along the corebody to selectively control the fluid flow and/or transfer conditionsthroughout the core body. Each aspect may be determined using methodsdisclosed herein.

In one or more embodiments, a core body (e.g., for a transfer apparatus)includes a structure having a plurality of connected unit cells, and atleast one unit cell of the plurality of connected unit cells has one ormore sidewalls that are curved and have an inner surface that defines atleast a portion of an inner passageway within and through the unit cell.The one or more sidewalls of the unit cell define multiple orifices suchthat a first fluid can ingress the unit cell through one of the orificesand can egress the unit cell through another of the orifices. The one ormore sidewalls include a cone disposed between at least some of theorifices of the unit cell. The one or more sidewalls have an outersurface, and a dimple is defined along the outer surface at the cone.The one or more sidewalls have an edge that extends around the orificesof the unit cell. The edges of different unit cells connect to eachother via the tubular extensions. The outer surface at least partiallydefines an outer passageway that is sealed from the inner passageway bythe one or more sidewalls of the unit cell. The outer passageway isconfigured to enable flow of a second fluid therethrough. The one ormore sidewalls of the unit cell are configured to transport one or moreof thermal energy from the first fluid or a component of the first fluidflowing in the inner passageway to the second fluid flowing in the outerpassageway without the first fluid mixing with the second fluid.

Optionally, the cone projects toward a center point of the unit cell.Optionally, the unit cell defines at least three orifices and the coneis located equidistant from at least three of the orifices. The cone maybe located equidistant from three of the orifices that are spaced apart120 degrees along a circumference of the unit cell. Optionally, the unitcell has a spherical shape defined by portions of the one or moresidewalls of the unit cell between the orifices and spaced apart fromthe cone. A wall thickness of the sidewalls of the unit cell may be noless than 0.3 mm and no greater than 1.5 mm. A diameter of the orificesof the unit cell may be at least ten times the wall thickness of the oneor more sidewalls of the unit cell. Optionally, a diameter of theorifices of the unit cell is greater than a diameter of the outerpassageway. Optionally, the core body is a single monolithic body, andthe multiple unit cells are connected at seamless interfaces. Thestructure may be composed of a metal material, a polymer material, orboth a metal material and a polymer material. Optionally, the unit cellsare arranged in rows that are stacked at least partially on top of oneanother, and a line extending from a center point of one unit cell in afirst row to a center point of another unit cell in a second row definesan angle no less than 30 degrees and no greater than 60 degrees relativeto a plane of the first row.

Optionally, the cone is a first cone and the one or more sidewalls ofthe unit cell include a second cone disposed between a different set ofthe orifices of the unit cell than the orifices between which the firstcone is disposed. The first cone and the second cone project in a commondirection. The structure has a height that extends from a bottom end ofthe structure to a top end of the structure, and the first cone of theunit cell is disposed below the second cone of the unit cell along theheight. The first cone may have a greater size than the second cone.

In one or more embodiments, a core body (e.g., for a transfer apparatus)includes a structure having a plurality of connected unit cells, and atleast one unit cell of the plurality of connected unit cells has one ormore sidewalls that are curved and have an inner surface that defines atleast a portion of an inner passageway within and through the unit cell.The one or more sidewalls of the unit cell define at least four orificessuch that a first fluid can ingress the unit cell through one of theorifices and can egress the unit cell through another of the orifices. Aportion of the one or more sidewalls disposed between three of theorifices has a triangular shape, and the three orifices are spaced apart120 degrees along a circumference of the unit cell. The one or moresidewalls have an edge that extends around the orifices of the unitcell. The edges of different unit cells connect to each other to atleast partially define outer passageways that are sealed from the innerpassageway of the unit cell and inner passageways of other unit cells bythe one or more sidewalls of the unit cells. The outer passageways areconfigured to enable flow of a second fluid therethrough. The one ormore sidewalls of the unit cells are configured to transport one or moreof thermal energy from the first fluid or a component of the first fluidflowing in the inner passageways to the second fluid flowing in theouter passageways without the first fluid mixing with the second fluid.

Optionally, the portion of the one or more sidewalls that has thetriangular shape includes a cone. The one or more sidewalls have anouter surface and a dimple is defined along the outer surface at thecone. The cone may project toward a center point of the unit cell.Optionally, the core body is a single monolithic body, and the multipleunit cells are connected together at seamless interfaces. Optionally,the unit cells are arranged in rows that are stacked at least partiallyon top of one another. A line extending from a center point of one unitcell in a first row to a center point of another unit cell in a secondrow may define an angle no less than 30 degrees and no greater than 60degrees relative to a plane of the first row. Optionally, the unit celldefines no more or less than six orifices.

In one or more embodiments, a method for forming a core body of atransfer apparatus includes additively manufacturing a core body bysequentially depositing layers of material at least partially on topeach other in a build direction to form a structure comprised of aplurality of connected unit cells. At least one unit cell of theplurality of connected unit cells has one or more sidewalls that arecurved and have an inner surface that defines at least a portion of aninner passageway within and through the unit cell. The one or moresidewalls of the unit cell define multiple orifices such that a firstfluid can ingress the unit cell through one of the orifices and canegress the unit cell through another of the orifices. The one or moresidewalls include a cone disposed between at least some of the orificesof the unit cell. The one or more sidewalls have an outer surface, and adimple is defined along the outer surface at the cone. The one or moresidewalls have an edge that extends around the orifices of the unitcell, and the edges of different unit cells connect to each other. Theouter surface at least partially defines an outer passageway that issealed from the inner passageway by the one or more sidewalls of theunit cell. The outer passageway is configured to enable flow of a secondfluid therethrough. The one or more sidewalls of the unit cell maytransport one or more of thermal energy from the first fluid or acomponent of the first fluid flowing in the inner passageway to thesecond fluid flowing in the outer passageway without the first fluidmixing with the second fluid.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise. “Optional” or “optionally” meansthat the subsequently described event or circumstance may or may notoccur, and that the description may include instances where the eventoccurs and instances where it does not. Approximating language, as usedherein throughout the specification and claims, may be applied to modifyany quantitative representation that could permissibly vary withoutresulting in a change in the basic function to which it may be related.Accordingly, a value modified by a term or terms, such as “about,”“substantially,” and “approximately,” may be not to be limited to theprecise value specified. In at least some instances, the approximatinglanguage may correspond to the precision of an instrument for measuringthe value. Here and throughout the specification and claims, rangelimitations may be combined and/or interchanged, such ranges may beidentified and include all the sub-ranges contained therein unlesscontext or language indicates otherwise.

Use of phrases such as “one or more of ... and,” “one or more of ...or,” “at least one of ... and,” and “at least one of ... or″ are meantto encompass including only a single one of the items used in connectionwith the phrase, at least one of each one of the items used inconnection with the phrase, or multiple ones of any or each of the itemsused in connection with the phrase. For example, “one or more of A, B,and C,” “one or more of A, B, or C,” “at least one of A, B, and C,” and“at least one of A, B, or C” each can mean (1) at least one A, (2) atleast one B, (3) at least one C, (4) at least one A and at least one B,(5) at least one A, at least one B, and at least one C, (6) at least oneB and at least one C, or (7) at least one A and at least one C.

This written description uses examples to disclose the embodiments,including the best mode, and to enable a person of ordinary skill in theart to practice the embodiments, including making and using any devicesor systems and performing any incorporated methods. The claims definethe patentable scope of the disclosure, and include other examples thatoccur to those of ordinary skill in the art. Other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

What is claimed is:
 1. A core body comprising: a structure defined by aplurality of unit cells that are interconnected and arranged in arepeating pattern, the unit cells having a respective cell body with acurved sidewall that defines a main cavity of the cell body, the unitcells having tubular extensions that physically connect the cell bodiesof different unit cells, the tubular extensions define flow channels,the curved sidewalls defining orifices to fluidly connect the maincavities of the different unit cells to the flow channels, the unitcells configured to permit flow of a first fluid through the structurewithin the main cavities of the cell bodies and the flow channels of thetubular extensions without the first fluid mixing with a second fluidthat is disposed in spaces between the unit cells, the curved sidewallof a first unit cell of the unit cells defining a first set of orificesand a second set of orifices, the first set of orifices fluidly connectto a first subset of the unit cells via a first group of the tubularextensions, the second set of orifices fluidly connect to a secondsubset of the unit cells via a second group of the tubular extensions,and the main cavity of the first unit cell having a dimension, along aportion of the curved sidewall between the first set of orifices and thesecond set of orifices, that is greater than cross-sectional dimensionsof the orifices in the first and second sets of orifices.
 2. The corebody of claim 1, wherein the first unit cell is in a first row of thestructure, the first subset of the unit cells is multiple unit cellsarranged in a second row, and the second subset of the unit cells ismultiple unit cells arranged in a third row, the first row being betweenthe second row and the third row.
 3. The core body of claim 2, whereinthe first subset of unit cells and the second subset of unit cells eachconsists of three unit cells.
 4. The core body of claim 3, wherein thefirst set of orifices includes a first orifice, a second orifice, andthird orifice spaced apart 120 degrees along a circumference of thefirst unit cell, and the second set of orifices includes a fourthorifice, a fifth orifice, and a sixth orifice spaced apart 120 degreesalong the circumference.
 5. The core body of claim 2, wherein the firstunit cell in the first row is not fluidly connected via any of the flowchannels through the tubular extensions to another unit cell in thefirst row.
 6. The core body of claim 1, wherein the portion of thecurved sidewall of the first unit cell between the first set of orificesand the second set of orifices has a spherical shape, and the dimensionof the main cavity is a cross-sectional diameter along the portion. 7.The core body of claim 1, wherein the core body is a monolithic body,and the unit cells are physically connected at seamless interfaces. 8.The core body of claim 1, wherein the main cavities of the cell bodiesand the flow channels of the tubular extensions collectively occupy agreater volume of the core body than the spaces between the unit cells.9. The core body of claim 1, wherein the curved sidewall of the cellbody of at least some of the unit cells includes a cone that projectstoward a center point of the respective cell body.
 10. The core body ofclaim 9, wherein the cone is located at a bottom portion of the cellbody relative to a direction of gravity.
 11. The core body of claim 9,wherein the cone of the first unit cell is a first cone that is disposedbetween the orifices in the first set, and the curved sidewall of thefirst unit cell includes a second cone that is disposed between theorifices in the second set.
 12. The core body of claim 1, wherein thecell bodies of the unit cells in a first area of the structure are atleast one of smaller or closer together than the cell bodies of the unitcells in a second area of the structure.
 13. A method comprising:additively manufacturing a core body by sequentially depositing layersof material at least partially on top each other in a build direction toform a structure, the structure defined by a plurality of unit cellsthat are interconnected and arranged in a repeating pattern, the unitcells having a respective cell body with a curved sidewall that definesa main cavity of the cell body, the unit cells having tubular extensionsthat physically connect the cell bodies of different unit cells, thetubular extensions defining flow channels, the curved sidewalls definingorifices to fluidly connect the main cavities of the different unitcells to the flow channels, the unit cells configured to permit flow ofa first fluid through the structure within the main cavities of the cellbodies and the flow channels of the tubular extensions without the firstfluid mixing with a second fluid that is disposed in spaces between theunit cells, the core body additively manufactured to define a first setof orifices and a second set of orifices through the curved sidewall ofa first unit cell, the first set of orifices fluidly connecting to afirst subset of the unit cells via a first group of the tubularextensions, the second set of orifices fluidly connecting to a secondsubset of the unit cells via a second group of the tubular extensions,and the core body additively manufactured to form the main cavity of thefirst unit cell having a dimension, along a portion of the curvedsidewall between the first set of orifices and the second set oforifices, that is greater than cross-sectional dimensions of theorifices in the first and second sets of orifices.
 14. The method ofclaim 13, wherein the core body is additively manufactured such that thefirst unit cell is in a first row of the structure, the first subset ofthe unit cells is multiple unit cells arranged in a second row, and thesecond subset of the unit cells is multiple unit cells arranged in athird row, the first row being between the second row and the third row.15. The method of claim 13, wherein the core body is additivelymanufactured such that the portion of the curved sidewall of the firstunit cell between the first set of orifices and the second set oforifices has a spherical shape, and the dimension of the main cavity isa cross-sectional diameter of the spherical shape.
 16. The method ofclaim 13, wherein the core body is additively manufactured such that thecore body is a monolithic body, and the unit cells are physicallyconnected at seamless interfaces.
 17. The method of claim 13, whereinthe core body is additively manufactured such that the main cavities ofthe cell bodies and the flow channels of the tubular extensionscollectively occupy a greater volume of the core body than the spacesbetween the unit cells.
 18. The method of claim 13, wherein the corebody is additively manufactured such that the curved sidewall of thecell body of at least some of the unit cells includes a cone thatprojects toward a center point of the respective cell body.
 19. A corebody comprising: a structure defined by a plurality of unit cells thatare interconnected and arranged in a repeating pattern, the unit cellshaving a respective cell body with a curved sidewall that defines a maincavity of the cell body, the unit cells having tubular extensions thatphysically connect the cell bodies of different unit cells, the tubularextensions define flow channels, the curved sidewalls defining orificesto fluidly connect the main cavities of the different unit cells to theflow channels, the unit cells configured to permit flow of a first fluidthrough the structure within the main cavities of the cell bodies andthe flow channels of the tubular extensions without the first fluidmixing with a second fluid that is disposed in spaces between the unitcells, the curved sidewall of a first unit cell of the unit cellsdefining a first set of orifices that fluidly connect, via a first groupof the tubular extensions, to a first subset of the unit cells, anddefines a second set of orifices that fluidly connect, via a secondgroup of the tubular extensions, to a second subset of the unit cells,and a collective volume of the main cavities of the cell bodies and theflow channels of the tubular extensions in the core body is greater thana collective volume of the spaces between the unit cells.
 20. The corebody of claim 19, wherein a portion of the curved sidewall of the firstunit cell between the first set of orifices and the second set oforifices has a spherical shape, the main cavity of the first unit cellhaving a cross-sectional diameter, along the portion between the firstand second sets of orifices, that is greater than cross-sectionaldimensions of the orifices in the first and second sets.